NNT and chromophobe renal cell carcinoma: Subgroup 4 tumors also showed increased expression of many genes that characterize chromophobe carcinomas and oncocytomas, including KIT and the mitochondrial genes NNT, FH, GOT1, GOT2, SLC25A5, ATP2B1, ATP5G3, ATP5B, and ATP6V1A (Figure 1H).